The invention relates to a heat exchanger unit which has heat exchanger ducts, formed by plates, for a coolant flow and for a flow to be cooled or to be temperature-controlled, and which is provided with corresponding inlets and outlets for the flows.
Heat exchanger units of said type are known for example from EP 916 816 B1. Said heat exchanger unit was used as an oil cooler in a motor vehicle. The coolant is conventionally the cooling liquid of the motor vehicle engine. From the coolant flow which cools the engine, a partial flow is branched off and used for oil cooling, then the partial flow is added to the coolant flow again after the exchange of heat with the oil has taken place, before then being recooled in a radiator. The branching of the partial flow is realized conventionally by means of corresponding valves or the like. The branched partial flow is often transported to the heat exchanger and back by means of lines.
EP 653 043B discloses another compact, housingless heat exchanger unit which is constructed from plates and which has an adapter plate. A coolant flow which has previously been branched off flows through said heat exchanger unit.
It is also known for coolant flows of different temperature to be mixed and passed through the heat exchanger in order to always be able to provide an optimum resulting oil temperature (EP 787 929 B1, U.S. Pat. No. 2,070,092).